1. Field of the Invention
The present invention generally relates to sports equipment and more particularly to an improved type of compound archery bow.
2. Prior Art
U.S. Pat. No. 3,486,495 to Holless Allen is directed to the pioneer compound archery bow. Many variations have been provided subsequently, but the original bow described in the above-listed patent has remained popular. Such a bow employs pulleys, levers or the like attached to its limbs to develop a mechanical advantage and/or a so-called draw force curve. Thus, through the use of, for example, an eccentrically mounted wheel disposed in the tip of each bow limb and cables connected thereto and trained thereover and also connected to the bowstring, a bow is provided which when drawn by the bowstring exhibits an initially increasing draw resistance until the so-called break-over point is reached in the latter portion of the draw, whereupon the resistance to drawing decreases. This enables the archer to draw a bow of overall greater draw weight and to more easily hold the bowstring at full draw, for greater shooting accuracy. Conventional non-compound bows become more difficult to draw as the drawing proceeds to full draw and thus are hard to hold at full draw.
Moreover, upon release of the bowstring, the compound bow gradually accelerates the arrow rather than initially applying maximum force to it, and ramming it as occurs with non-compound bows. Therefore, the compound bow bends the arrow less than conventional bows, allowing more usable force to be directed along the length of the arrow shaft, propelling the arrow more rapidly toward the target, rather than dissipating the driving force in arrow shaft bending. Thus, lighter, thinner walled arrows can be used, resulting in much greater arrow speed, a flatter arrow flight trajectory and greater shooting accuracy.
However, because of less side bending of the arrow shaft and the presence of the cables adjacent the bowstring, there is a danger when using a compound bow that the arrow feathers or vanes will strike the cables and/or arrow rest, causing them to wear and deflect the arrow from its intended flight path. It is now conventional to solve this problem by connecting a cable guard to the bow riser. Such a guard is an arm which extends laterally and rearwardly from the riser and holds the cables on the lateral side thereof away from the arrow window, bowstring and arrow path. This, however, places a twisting force or side torque on the limb tips which can cause their premature failure, particularly if the bowstring breaks suddenly, shocking both limbs. In such instances, the limbs frequently break, causing great danger to the archer.
Most compound bows are in any event difficult to restring and require a bow press or string changer device, neither of which are likely to be available if the archer is on a hunting trip, or even on the target or field range. Moreover, most compound bows are also difficult to adjust in draw weight and draw length. Most such adjustments cannot be made without some dismantling of the bow. A further difficulty is that the opposite limb tips have to be interconnected through the cables in order to provide the block and tackle effect, achieving mechanical assistance and simultaneous roll-over (break-over) of the wheels or levers. The cables have to be crossed over each other in order to function properly and wear of both cables may occur over a period of time. Breakage of the bowstring or a cable simultaneously adversely affects the limbs, cables and bowstring.
Accordingly, there is a need for an improved compound archery bow which will provide easier adjustment of draw length and draw weight to meet precise requirements for improved performance of the bow and ideal arrow flight. Such bow should also be easier to restring, obviating the need of complicated cumbersome restringing devices, and should provide greater safety to the archer and bow in case of bowstring breakage. Preferably, the bow should also incorporate better protection against limb torque while providing necessary cable clearance for unimpeded arrow flight.